1. Field of the Invention
The present invention relates to a character display device (hereafter character display) and method therefor which display characters on a display section of a personal computer or a navigation device or the like.
2. Description of the Related Art
FIG. 1 shows a conventional character display as for example disclosed in JP-A 4-352193. In the figure, reference numeral 1 denotes a character series designation means which designates a character series to be displayed on a display of a navigation device for example. 2 is a reference line designation means which designates a reference line (sloping line) which expands a character series. 3 is a character position determination means which determines an expansion position of a character series which is expanded on said reference line.
FIG. 2 is an expansion diagram explaining the expansion of a character series with respect to a reference line.
The operation of the conventional character display will be explained below.
When a character series is displayed on a display of a navigation device, firstly a user designates a character series to be the object of display using a character series designation means 1. When the character series to be the object of display is designated, a number (integer) of characters in said character series and a character width a of each character (the same value for all character) comprising the character series is determined.
When a user designates a character series to be displayed, a reference line which expands a character series is designated using a reference line designation means 2. The designation of the reference line is performed by inputting reference coordinates for the initial point (x0, y0) and the final point (x1y1) of the sloping line acting as the reference line.
In this way, when a character series to be the object of display and a reference line are designated, a character position determining means 3 calculates a lower left coordinate (hereafter character coordinate) of each character using the lower left of the screen as an origin (0, 0), when the character series is expanded on a straight line in a horizontal direction.
The coordinates (x′, y′) of the nth character A in a character series expanded on a straight line in a horizontal direction are calculated as follows:x′=x0+(n−1)ay′=y0
The character position determination means 3 calculates the character coordinates of each character in a character series expanded in a straight line in a horizontal direction and then calculates the character coordinates of each character when the character series is rotated by a slope α of a reference line about the initial point (x0, y0) of the character series.
The coordinates (x, y) of the nth character A in a character series expanded on a reference line are calculated as follows:x=x0+(n−1)a·cos αy=y0+(n−1)a·sin α
Since the conventional character display is constructed as discussed above, it is possible to display character series at an arbitrary slope. However when the character series is sloped on display, it is necessary to rotate each character comprising the character series. Thus the problem has arisen that the dot pattern forming each character destroyed by such variation (when the rotational angle of the character is 90°, 180°, 270°, there is no variation in the dot pattern even if the characters are rotated). Therefore the presentation of the characters has suffered as a result.
Furthermore, since the character width a of each character comprising the character series calculates the character coordinates on the basis that they are normally the same, for example when narrow characters such as “i” and “l” are present, one section of the character series will be distorted and the presentation of the character series will suffer as a result.